• 한국표면공학회지
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• 제43권4호
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• pp.180-186
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• 2010

$TiO_2$ nanotubes were formed on Ti by anodizing in 1 M $H_3PO_4$ + 0.3 M HF and 0.1 M $NH_4F$ + 2% $H_2O$ in ethylene glycol, and their surface and cross-sectional morphologies were observed using FE-SEM as a function of anodizing time and applied voltage. The cross-section of the $TiO_2$ nanotubes was readily observed from the small pieces of nanotubes remaining near the scratch lines after scratching of the anodized surface. $TiO_2$ nanotubes was observed to grow faster and thicker in non-aqueous solution than in aqueous solution. Diameter of $TiO_2$ nanotubes was proportional to the applied voltage, irrespective of the type of the electrolyte, and it is recommended to use non-aqueous solutions for the preparation of larger diameter of $TiO_2$ nanotubes.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.282-285
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• 2009

This study presents preparation and characterization of composite membranes based on ionic liquids. The ionic liquids act as water in sulfonated membranes. On the behalf of ionic conduction through ionic liquid inside the membranes, non-aqueous membranes showed Arrenhius dependence on temperature with no external humidification. It was implied that hopping mechanism of proton was dominant in the ionic liquid based membranes. In addition, small angle X-ray (SAXS) studies provided the information on morphology of ionic clusters formed by the interaction between sulfonic acid groups of the polymers and ionic liquids. The SAXS spectra showed matrix peaks, ionomer peaks and Prodo's law for Nafion based composite membranes and only matrix peaks for hydrocarbon based ones. However, ionic conductivity and atomic force microscopy (AFM) images showed the clear formation of ionic clusters of the hydrocarbon based composite membranes. It implies for ionic liquid based high temperature membranes that it is important to use sulfonated polymers as solid matrix of ionic liquid which can form clear ionic clusters in SAXS spectra.

• 전기화학회지
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• 제6권2호
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• pp.141-144
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• 2003

Proton conducting polymeric gels as the electrolytes of electrochemical capacitors have been prepared by two different methods: 1) swelling a polymethacrylate-based polymer matrix in aqueous solutions of inorganic and organic acids, and 2) polymerizing complexes of anhydrous acids and prepolymers with organic plasticizer. The FT-IR spectra strongly suggest that the carbonyl groups in the polymer matrix interact with protons from the doped acids. High ionic (proton) conductivity in the range of $6\times10^{-4}-4\times10^{-2}\;S\;cm^{-1}$ was obtained at room temperature for the aqueous gels. The non-aqueous polymer complexes showed rather low ionic conductivity, but it was about $10^{-3}\;S\;cm^{-1}\;at\;70^{\circ}C$ for the $H_3PO_4$ doped polymer electrolyte. The mechanisms of ion (proton) conduction in the polymeric systems are discussed.

• Applied Microscopy
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• 제23권2호
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• pp.1-10
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• 1993

The effect of electrolyte on the extraction replicas of the precipiates in 3% Si steel was investigated. Three Kinds of electrolyte, 2% Nital solution (2% nitric acid+methanol; acid solution),, Sodium Citrate solution (5% sodiumcitrate+1% KBr+0.5KI+$H_{2}O$; aqueous neutral solution) and 10% AA solution (10% acetylacetone+ 1% tetramethylammoniumchloride+methanol; non-aqueous neutral solution), were compared. The preciptiates in 3% Si steel were dissolved in 2% Nital, but they were not dissolved in the Sodium Citrate and 10% AA solution. In Sodium Citrate solution, however, large second artifacts were introduced during sample preparation. Therefore 10% AA solution was found to be most useful for the preparation of extraction replica. The electrolysis condition of a matrix and precipitates were also checked by the measurement of potential-current curve in 10% AA solution. The matrix was electrolyzed at -400mV with respect to SCE(Saturated Calomel Electrode). In contrats precipitates were electrolyzed above 300mV. Precipitates were respected to be stable in 10% AA solution in the range of $-380mV{\sim}-300mV$ usually used to prepare extraction replicas.

• 한국환경보건학회지
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• 제40권2호
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• pp.137-146
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• 2014

Objectives: Feasibility of electrochemical oxidation of the aqueous non-biodegradable wastewater such as cationic dye Rhodamine B (RhB) has been investigated in an electrochemical reactor with solid polymer electrolyte (SPE). Methods: Nafion 117 cationic exchange membrane as SPE has been used. Anode/Nafion/cathode sandwiches were constructed by sandwiching Nafion between two dimensionally stable anodes (JP202 electrode). Experiments were conducted to examine the effects of applied current (0.5~2.0 A), supporting electrolyte type (0.2 N NaCl, $Na_2SO_4$, and 1.0 g/L NaCl), initial RhB concentration (2.5~30.0 mg/L) on RhB and COD degradation and $UV_{254}$ absorbance. Results: Experimental results showed that an increase of applied current in electrolysis reaction with solid polymer electrolyte has resulted in the increase of RhB and $UV_{254}$ degradation. Performance for RhB degradation by electrolyte type was best with NaCl 0.2 N followed by SPE, and $Na_2SO_4$. However, the decrease of $UV_{254}$ absorbance of RhB was different from RhB degradation: SPE > NaCl 0.2 N > $Na_2SO_4$. RhB and $UV_{254}$ absorbance decreased linearly with time regardless of the initial concentration. The initial RhB and COD degradation in electrolysis reaction using SPE showed a pseudo-first order kinetics and rate constants were 0.0617 ($R^2=0.9843$) and 0.0216 ($R^2=0.9776$), respectively. Conclusions: Degradation of RhB in the electrochemical reactor with SPE can be achieved applying electrochemical oxidation. Supporting electrolyte has no positive effect on the final $UV_{254}$ absorbance and COD degradation. Mineralization of COD may take a relatively longer time than that of the RhB degradation.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.93-93
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• 2008

니켈도금은 각종 소지 상에 직접적이고 밀착성이 양호하고, 변색이 적고 방청력이 크며, 경도, 내식성, 내마모성 및 유연성이 우수하다. 또한 최근 활발히 진행되고 있는 광촉매 연구에 $TiO_2$는 우수한 광화학적 안정성, 효과적인 전하분리, 높은 산화 환원력 및 상업적 적용성을 갖기 때문에 니켈도금용액에 $TiO_2$를 첨가하며 복합도금을 행함으로써 니켈이 가지고 있는 기존의 우수한 특성에 $TiO_2$의 광분해 효과를 부과시킴 으로써 그 특성이 한층 더 향상되는 것을 알수있다. 본 연구에서는 수용액전해질과 비수용액 전해질에서의 Ni-$TiO_2$ 복합도금의 특성을 비교 분석해보았다. 동전위(Potentiodynamic)실험 및 순환전위(Cyclic Voltammetry)실험을 하였으며, 도금층의 특성 및 두께는 OM,SEM을 이용하여 분석하였다. 또한 복합도금 촉매 전극에 의한 광분해 효과를 보기 위해서 UV램프를 이용하여 분석하였다.

• 한국표면공학회지
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• 제35권1호
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• pp.17-32
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• 2002

Electroplating methods by molten salts and non-aqueous melts were employed for aluminium coating on STS 316L stainless steel. After coated with Ni or non-coated surface on stainless steel, Al pulse plating was carried out in two different types of electrolytes at room temperature. The Al layer from $AlCl_3$-TMPAC melts could not obtain appreciable thickness for engineering application due to chemical reactions between deposits and moisture of air. However, The Al coating by pulse plating in the Ethylbenzene-Toluene-$AlBr_3$ systems was found to be solid coating layer with a few $\mu\textrm{m}$ scale. The conductivity of Ethylbenzene-Toluene-$AlBr_3$ electrolyte was as functions of time and agitation. By seven days exposure after mixing of the electrolyte, Al-deposited layer shows uniform and near by pore-free with high current density (higher than 30mA/$\textrm{cm}^2$). The roughness and imperfection of coating layer were decreased with a increasing agitation speed. It was found that the optimum condition for the Al pulse plating on the 316L stainless steel was a 400mA peak current, duty cycle, $t_{on}$ $t_{ off}$=3ms/1ms, and a current density of 30mA/$\textrm{cm}^2$.

• 공업화학
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• 제18권3호
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• pp.291-295
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• 2007

전기화학적으로 용량이 큰 활물질을 얻기 위한 수단으로 니들 코크스를 $NaClO_3$과 70 wt%의 $HNO_3$으로 구성된 수용액을 이용하여 산화처리를 하였다. $NaClO_3$/니들 코크스의 질량비가 7.5배인 수용액에서 산화 처리한 결과, 니들 코크스는 산화흑연 구조로 상변이가 일어나고, 또한 산소의 함유량의 증가와 함께 층간거리는 $6.9{\AA}$으로 확대되었다. 한편, 산화 니들 코크스의 전기이중층 커패시터용 분극 전극으로서의 전기화학적 특성은 acetonitrile의 용매에 각각 1.2 M의 TEABF4 (tetraethylammonium tetrafluoroborate)와 $TEABF_4$ (triethylmethylammonium tetrafluoroborate)의 전해질이 함유된 유기용액을 각각 사용하여 조사하였다. 1.2 M $TEABF_4$/acetonitrile의 전해액을 사용한 커패시터 셀은 1.2 M $TEABF_4$/acetonitrile의 전해액을 사용한 커패시터 셀에 비해 전극저항은 $0.05{\Omega}$로 낮았고, 2 전극 기준으로 0~2.5 V에서 측정한 용량 및 부피 당 용량은 32.0 F/g와 25.5 F/mL으로 높은 수치를 나타내었다. 이러한 전기화학적 거동을 천연흑연 구조에서의 층간 거리와 전해질의 양이온 크기와의 상관관계로 논의하였다.

• 한국가스학회지
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• 제26권3호
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• pp.21-26
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• 2022

아연은 인체에 유해한 카드뮴을 대체하여 금속재료에 수소가스가 침투하거나 금속재료 내부로부터 수소가 누출되는 것을 방지하기 위한 친환경 코팅 재료로 주목받고 있다. 일반적으로 수성 및 산성 분위기에서 수행되는 아연(Zn) 및 아연 합금의 전기도금은 낮은 쿨롱 효율, 부식 및 수소 누출과 같은 단점이 있어 산업적 이용이 어렵다. 본 연구에서는 염화콜린과 에틸렌글리콜을 이용하여 Deep-eutectic solvent를 합성하고 이를 용매로 사용하여 아연 도금용 전해질을 제조하여 STS 304 기판 위에 전기 도금하였다. 주사전자현미경(SEM)과 원자힘현미경(AFM)을 이용하여 표면 미세구조와 조도를 관찰하였다. X선회절분석(XRD)을 이용하여 도금 막의 결정구조를 분석하였다. 마지막으로 수소를 주입한 STS 304 기판에 최적화된 Zn 도금액을 코팅한 시료의 수소 방출 방지 효과를 분석하였다.

• 대한화학회지
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• 제53권2호
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• pp.159-165
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• 2009

2-Amino-5-Substituted-1,3,4-Oxadiazoles의 합성은 비분활된 셀에서 포텐셜 전기분해의 제어하에 백금전극의 세미카바존 전기적 산화로부터 수행되었다. 이것은 유기화학 합성분야에서 환경적으로 양호한 방법이다. 아세트산 및 아세트니트릴, 무수용매와 리튬 과염소산염 이 전기적 산화에서 전기분해을 위하여 사용 되어졌다. 생성물은 IR, $^1H$-NMR, $^{13}C$-NMR 그리고 원소분석을 통해 구조분석 하였다.